A Simple Procedure for the Side-Chain Substitution of 2-Alkyl-3<b>
<i>H</i>
</b>-quinazoline-4-thiones: Application in Synthesis
作者:Gamal A. El-Hiti
DOI:10.1055/s-2004-815923
日期:——
Double lithiation of 2-alkyl-3H-quinazoline-4-thiones at nitrogen and at the α-hydrogen of the 2-alkyl group (Me, Et, Pr) has been achieved with n-butyllithium at -78 °C in anhydrous THF under nitrogen. Reactions of the dilithium reagents obtained with various electrophiles (iodomethane, iodoethane, 1-bromobutane, D2O, benzaldehyde, 4-anisaldehyde, butan-2-one, cyclohexanone, benzophenone, phenyl isothiocyanate, tetraisopropylthiuram disulfide) gave the corresponding modified 2-substituted 3H-quinazoline-4-thiones 4-22 in excellent yields.
2- 烷基-3H-
喹唑啉-4-
硫醚在氮和 2-烷基(Me、Et、Pr)的δ-氢处与
正丁基锂在-78 °C的无
水四氢呋喃中在氮条件下实现了双重石化作用。将得到的二
锂试剂与各种亲电体(
碘甲烷、
碘乙烷、1-
溴丁烷、D2O、
苯甲醛、
4-甲氧基苯甲醛、丁-2-酮、
环己酮、
二苯甲酮、异
硫氰酸苯酯、二
硫化四异丙基
秋兰姆)反应,可以得到相应的改性 2-取代 3H-
喹唑啉-4-
硫酮 4-22,收率极高。